The legendary Brazilian striker, who lined up for both clubs during his illustrious career, was on target as Los Blancos ended an agonising wait for a win at the home of their great rivals with a 2-1 success in Catalunya.
"Real Madrid and Barcelona was my first great derby in Europe,” he told Globoesporte.
“For Real, my unforgettable moment was when we defeated Barcelona in their home for the first time in 17 years. It was truly unforgettable.”
However, the now-retired forward admitted that Madrid have it all to do in the second leg of their Copa del Rey quarter-final tie with Barca on Wednesday night, with a 2-1 aggregate deficit to overturn.
"It's very difficult to win at Barcelona today,” he mused. “Even for a team full of great players like Real. Everyone needs to have a great day and be very focused.”
Ronaldo spent one season with Barca between 1996 and 1997 before returning to Spain with Madrid in 2002.
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